Patent Document 1 proposes techniques for presenting work environment instruction about installation of an air conditioner to an operator working for the installation. According to Patent Document 1, a display portion indicating the work environment instruction is situated in a work site so that the operator easily finds the work environment instruction.
The techniques of Patent Document 1 do not always make the operator do confirmation based on the work environment instruction although the techniques of Patent Document 1 may provide the work environment instruction for the operator. For example, when the operator fails to watch the display portion indicating the work environment instruction or when the operator neglects access to the work environment instruction through a QR code (registered trade mark) displayed on the display portion, a trail run of the air conditioner may be executed under wrong installation.